
  #include "stdio.h"
  #include "6grad.c"
  main()
  { int i;
    double eps,x[4];
    double a[4][4]={{5.0,7.0,6.0,5.0},
                           {7.0,10.0,8.0,7.0},
                           {6.0,8.0,10.0,9.0},
                           {5.0,7.0,9.0,10.0}};
    double b[4]={23.0,32.0,33.0,31.0};
    eps=0.000001;
    grad(a,4,b,eps,x);
    printf("\n");
    for (i=0; i<=3; i++)
       printf("x[%d]=%13.5e\n",i,x[i]);
    printf("\n");
  }

